When me or my friend die in our single player world, sometimes we lose things immediately. Ex: I killed him once, and he had to get to base from world spawn (another bug) and when he got back in like 3 minutes all his things disappeared Which is weird because it takes 20 minutes for something to despawn. Sometimes only some of our things disappear.
We're tracking this issue at MCPE-121025, so I will resolve and link this ticket as a duplicate. Note that items despawn after 5 minutes, not 20 minutes.